The present invention relates to a mechanism for enveloping large round bales, formed in a bale-forming chamber, with a wrap material such as plastic sheet or net and more particularly relates to a housing for holding a supply of such wrap material in a position for being fed into the bale-forming chamber.
Heretofore, designers of wrap material housings used for holding material for being dispensed for wrapping a bale have taken into consideration the ease of loading a roll of material into the housing and the desirability of applying a constant drag or braking force on the loaded roll of material during the wrapping process. For example, U.S. Pat. No. 4,787,193 granted on 29 Nov. 1988 discloses such a housing having a cover which may be pivoted to a lowered, substantially inverted position for receiving a roll of wrapping material and then raised to deposit the roll on a floor or bottom wall of the cover. This patent also discloses a spring biased brake member mounted to the cover and operable for biasing the roll into contact with a fixed forward wall of the housing and the floor with a force which remains substantially constant as the diameter of the roll diminishes during usage.
Another example of such a housing is that disclosed in U.S. Pat. No. 4,956,960 granted on 18 Sep. 1990. This housing includes a cover which pivots upwardly to a raised position, in which it is retained by a pair of gas springs, to permit a pivotally mounted wrap material loading arm, which is shaped for cradling a roll of wrapping material when lowered to a load position, to be raised to deposit the roll of material on a fixed bottom wall which is curved convexly upwardly and extends downwardly toward the bale-forming chamber and a vertical abutment wall such that an approximate constant wedging or braking force is exerted on the roll as its diameter diminishes during wrapping of the material about a bale.
While the manner of loading a roll of wrap material into these known housings is generally satisfactory, the structures for doing such are relatively complex and/or expensive. Also, it has been found that while these known structures function to produce substantially constant braking forces on the roll during the wrapping of a bale under ideal conditions, the roll braking forces of both are sensitive to the condition of the front wall and floor surfaces supporting the wrap material during wrapping operation. Specifically, the braking force is influenced by such variations in surface condition as may be caused by paint wearing off and/or by the surface becoming corroded.